> (When was the last time you wrote a while or repeat until loop, or a recursive function that didn’t iterate over an input? Iterating until a convergence crit

> (When was the last time you wrote a while or repeat until loop, or a recursive function that didn’t iterate over an input? Iterating until a convergence criteria is met is fairly common in numerical calculations. It's also fairly common when dealing with graphs that may not have a beginning or an end in a conventional sense. PageRank does both of these things, for example.